The present invention relates to a multi-row keyboard for typewriters or similar machines.
More specifically, the invention relates to a keyboard comprising a set of keys consisting of individual key elements in which the keyheads are mounted to the plungers of the key elements in a position compensating for the inclined position of the set of keys.
As the result of studies for adapting the working means to the peculiarities and inherent laws of the working man, and pursuant to the handbook of office medicine and ergonomics "Arbeitswissenschaft fur die Buropraxis" by Dr. med. Th. Peters, Schilling Verlag, Herne, 1973, page 208, it was found to be appropriate to adapt the set of keys of a multi-row keyboard to the different curvature and movement of the fingers up to a certain degree. This can be achieved by arching the set of keys upwardly to become slightly shell-shaped (dished) in cross section.
In "Honeywell's Keyboard Handbook", Code No. 84-20164-0 1072, Section II, pp. 4 and 5, this recommendation is complied with in that an arched set of keys can be formed by using specifically shaped keyheads. This requires different types of keyheads for each row of keys, which must have different heights for achieving the dish effect, and in which the keyhead surfaces from row to row must be molded to include a different angle.
There is no complete international standardization of keyboard arrangements. Although considerable agreement has been reached, there are still quite a number of characters whose arrangement within the keyboard differs from country to country. For keyboard equipment manufacturers having a high export rate it is necessary, therefore, to arrange the keyboards in the way as customary in the respective country. It frequently occurs that characters are changed from one row of types into another. When using individually shaped keyheads, this requires that for each of these characters a plurality of keyhead designs must be manufactured and kept in stock. Moreover, during assembly, care has to be taken that each time the correct type of keyhead is mounted.
It is the object of the present invention to restrict the manufacture of keyheads to the absolutely necessary extent, and to simplify the assembly of the keyboard.